I think when the computer detects a fault (broken wire, bad sensor etc) it kicks the lights on and disables the ABS system indefinitely...which may explain why there was no power to the module. On the back of the hub right under the axle is where the wire for the ABS comes out, they are notorious for rubbing/breaking. Best is to get a mirror to see behind or sometimes just snap a pic with a digital camera behind the tire with the flash on, let you first take a look at the wiring for any obvious problems before you tackle one side or another. ABS codes need a special scanner from a dealership or garage, they are not OBD2 codes.
